Reclosable fastener assemblies are useful for sealing thermoplastic bags. Such fastener assemblies often include a plastic zipper and a slider. Typically, the plastic zippers include a pair of interlockable fastener elements which form a closure. As the slider moves across the fastener strips, the fastener is opened or closed.
The fastener elements in plastic zippers can take on various configurations. For example, U.S. Pat. No. 5,140,727 describes interlocking rib and groove elements, whereas U.S. Pat. No. 5,007,143 describes rolling action closure elements, and U.S. Pat. No. 4,747,702 describes closure elements that are U-shaped with interlocking hooks.
The sliders for opening or closing the reclosable fasteners are generally shaped so that the slider straddles the profiles. The sliders often include a separator that is inserted between the fastener strips through the closure elements in order to open the fastener. Such a slider is described in U.S. Pat. No. 5,067,208. In other types of sliders, the separator does not penetrate the closure elements, but rather, slides above the closure elements on a specially adapted track located above the closure elements, as described in U.S. Pat. No. 5,007,143. The separators have various shapes. U.S. Pat. No. 5,007,143. The separators have various shapes. For example, U.S. Pat. No. 3,173,184 describes a V-shaped separator, while U.S. Pat. No. 5,067,208 describes a tapered separator with a rounded end.
One of the important features of such reclosable fastener assemblies are the endstops, which prevent the slider from falling off the end of the fastener when the slider reaches the end of the fastener. Endstops have taken on various configurations, such as, for example, riveted end clamps such as those described in U.S Pat. Nos. 5,067,208 and 5,161,286; transverse end stops made from molten material of the fastener strips, as described in U.S. Pat. No. 5,088,971; reciprocating anvils, as described in U.S. Pat. No. 5,131,121; tubular end stops, as described in U.S. Pat. No. 5,405,478; a window structure combined with sealed zipper ends, as described in U.S. Pat. No. 5,442,837; or plastic end clips fused to the zipper as described in U.S. Pat. No. 5,448,807.
Another important feature in some of the closures of the prior art is a docking station, which is means for maintaining the slider in the closed position. Docking stations have taken on various configurations, such as, for example, a notch structure such as that disclosed in U.S. Pat. No. 5,067,208; or a notch structure with diverging ends such as that disclosed in U.S. Pat. No. 5,301,395; or latching means, such as a detent on the slider together with a protrusion on the zipper as disclosed in U.S. Pat. No. 5,189,764.
One disadvantage of these endstops and/or docking stations is that they may be expensive because additional plastic must be added to the fastener to form the endstop. Another disadvantage of these endstops and/or docking stations is that they may require that holes be cut into them, thereby increasing the risk of leakage through the fastener. It would be an advance in the art of reclosable fastener assemblies to minimize leakage through the closure with a simplified endstop design and a simplified docking station design.